Storm Water Filtration System Using Box Culverts

ABSTRACT

An apparatus and method for use in conjunction with box culverts to collect and filter or otherwise treat dirty or polluted storm water runoff or other fluid is disclosed. One or more filter devices with filter media is used in connection with a box culvert. One or more internal bypass assemblies is disposed along a vertical surface in the box culvert. One or more concrete slabs is installed within the box culvert and forms a false floor below the filter devices. The false floor provides an annular space through which fluid can bypass the filter devices and be released to a drainage system.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.61/681,097 filed on Aug. 8, 2012, which is herein incorporated byreference in its entirety.

FIELD OF THE INVENTION

The present invention relates generally to apparatuses and methods fortreating or filtering fluids, and more particularly to apparatuses andmethods for use in conjunction with box culverts to collect and filterstorm water runoff.

BACKGROUND OF THE INVENTION

Impervious surfaces and other urban and suburban landscapes generate avariety of contaminants that can enter storm water, polluting downstreamreceiving waters. These contaminants can include heavy metals, oils, andgreases, organic toxins, as well as trash and debris. In response totighter guidelines imposed by environmental and regulatory agencies, thecontrol of pollution, silt and sediment found in storm water runoff andother sources of water is receiving ever-increasing attention at alllevels of federal, state, and local government. Federal and stateagencies have issued mandates and developed guidelines regarding theprevention of non-point source (storm water caused) pollution thatrequire action by governmental entities. These mandates affect themanagement of water runoff from sources such as storms, slopes, andconstruction sites. In addition, there are many other laws andregulations in place that restrict the movement or disposal ofsignificant amounts of water. Such laws and regulations have asignificant impact on, for example, the ways that states,municipalities, highway authorities and other responsible bodies candrain or otherwise dispose of storm water runoff or other water fallingon or passing over highways, roadways, parking lots and the like.

Typical storm water filtration systems used to reduce pollutant loadingin runoff from urban developments include known filter devices housed ina vault configuration. The filter devices capture and retain sediment,oils, metals and other target constituents close the source and reducesthe total discharge load. As illustrated in FIG. 1, the filter devicescan include cylindrical filter cartridges with filter media, housedwithin upright walls, such as the Perk Filter™ (KriStar Enterprises,Inc.; Santa Rosa, Calif.). A filter device is also described in U.S.Pat. No. 6,241,882, which is entitled “Sump & Filter Device For DrainageInlets” and is assigned to KriStar Enterprises, Inc.

Referring to FIG. 1, storm water can enter the filtration system via aninlet opening 101 through an outer wall 102 into a first chamber of thevault. The first chamber includes a gallery floor 103 and a floor slab104 beneath the gallery floor. The storm water then flows through one ormore bypass manifold assemblies 105, past an internal wall 106 that ispoured such that it is monolithic with the outer wall or outer walls.The bypass manifold assembly includes an inlet bypass floatable weir 107at an upper portion that obstructs the flow of gross pollutants in thewater. The bypass manifold assembly also includes an inlet bypassmanifold weir 108 located at a lower portion that allows fluid toaccumulate. During periods of routine flow, storm water moves throughthe bypass manifold assembly into an adjacent filter chamber, where itis filtered by one or more known devices, such as filter cartridges 109containing filter media. Filtered flows then move through an outletopening 110 along an outer wall 111. During periods of peak flow, stormwater is allowed to accumulate in the first chamber until it reaches theheight of the lower bypass weir, also called an inlet bypass manifoldweir. Bypass flows pass over the weir and are directed to a lowerannular space, separate from the chamber with filter media, before thestorm water exits the system. Angled brackets support 112 acts as asupport frame for the platform on which the filter media rests.Expansion bolts 113 are used to join the angled bracket to the platform.

Because the vault and the components must be separately constructed,time and effort is required to size and manufacture different vaults andcomponents for different flow capacities. Moreover, the platform onwhich the filter devices rest must be sized and designed to securely fitthese different vault structures. In practice, the filtration capacityis often limited by the size of an individual vault. Installation of thevarious components in the system may require additional effort,particularly for larger systems with a large number of filter devicesand increased treatment capacities.

Thus, there exists a need for practical and economical storm waterfiltration methods and apparatuses that can be easily manufactured andinstalled at a site. There is also a need for a storm water filtrationsystem that can efficiently handle bypass flows during peak events.There is also a need for a storm water filtration system that can beconfigured to handle different levels of storm water flows.

SUMMARY OF THE INVENTION

The present invention provides more effective methods and apparatusesfor filtering and treating polluted or dirty water, such as storm waterrunoff, using existing box culverts. The invention relies on the supportstructures in the box culvert to install a “false floor” that supportsthe filter media and allows filtered flows to pass along the top. Thefalse floor also creates an annular space below to allow for unfilteredbypass flows from the system.

A conventional box culvert includes a rectangular-shaped drain or pipethat channels water flow under roads, parking lots, railroads, orsimilar obstructions. Other shapes such as arched, round, circular, orcurved culverts are also available. Box culverts are generally availableas precast units that can be manufactured before installation. Theyprovide both load bearing strength and structural integrity. Becausethey are readily available and easily sourced for constructionapplications, box culverts provide a versatile, structurally strong, andcost effective structure to support storm water filtration systems. Boxculverts are available in various standard sizes and known materials,such as precast concrete. Thus, one advantage of the use of a boxculvert in the present invention is the ability to use existingstructures that are available and manufactured according to standardindustry sizes. This allows for ease of manufacture, as well as quickerand more economical installation.

Another advantage of the present invention is the use of one or morefalse floors installed in an existing box culvert to provide a separate,alternate path for storm water flow. A false floor is set within the boxculvert. It provides a platform or mounting surface on which filterdevices may rest. It also creates an annular space beneath the floorthrough which unfiltered flows moving from the bypass assembly can move.In this way, the false floor separates filtered and unfiltered stormwater flowing through the same system.

Another advantage of the present invention is the flexibility toconfigure and use additional filter sections in box culverts, as neededfor a given site or filtration capacity. Because the box culverts aremodular, a plurality of box culverts may be used in differentconfigurations, depending on the needs of a given site or constructionproject. The system can be expanded to accommodate multiple units. Inaddition, filter units can be added or removed as needed.

Another advantage of the present invention is the use of one or moreinternal bypass assemblies disposed within one or more walls of theinlet section. The internal bypass assembly provides an alternate pathfor storm water during peak flow events by diverting storm water from afilter section into an annular space below the filter section.

A further advantage of the present invention is the reduction of theworkload required of one more particular filter unit in terms of theamount of sedimentation, silt and pollution that they are required toremove over the course of its life span. These advantages can beaccomplished by installing multiple filter banks, such that at least aportion of storm water runoff or other passing fluids can be processedthrough multiple banks during high flow events.

Another advantage of the present invention is the ability to retaingross pollutants, such as trash, debris, and coarse sediment, within afiltration system, without impeding peak flow bypass needs. The presentinvention allows for trash capture through the use of a bypass manifoldassembly located within a box culvert.

Yet another advantage of the present invention is the provision of moreeffective methods and apparatuses for filtering and treating polluted ordirty water, such as storm water runoff, that passes over highways,roadways, parking lots and the like, such that whatever fluid eventuallymakes its way into a final drainage infrastructure or destination islikely to be cleaner. This advantage is realized by providing anapparatus and method for processing water runoff or other fluid whensuch fluid enters a water treatment system. These and other usefulobjects are achieved by the improved apparatuses and methods disclosedherein.

One embodiment of the present invention provides an apparatus adapted tocooperatively engage with a box culvert, comprising: an inlet sectiondisposed within a box culvert; at least two outer walls shared with thebox culvert; at least one internal bypass assembly disposed within awall of the inlet section comprising two substantially vertical weirs;at least one filter section in fluid communication with the bypassassembly comprising at least two inner walls and filter media; at leastone bottom platform disposed within the box culvert and under at least aportion of the filter section, wherein the space between a lower surfaceof the platform and an upper surface of the box culvert forms an annularspace through which unfiltered fluid is allowed to flow; and an outletsection in fluid communication with the filter section, wherein saidoutlet section comprises at least two outer walls shared with a boxculvert.

Optionally, the apparatus may comprise an access riser along a topsurface of the box culvert, wherein the access riser includes a moveableaccess cover. The apparatus may further comprise multiple filtersections, wherein a substantially vertical separation plate is disposedbetween adjacent filter sections. The apparatus may further comprisemultiple bottom platforms, wherein a closure plate separates adjacentplatforms. The platform of the apparatus may optionally compriseconcrete.

In another embodiment, the present invention provides a method ofprocessing fluid comprising the steps of selecting an inlet of a boxculvert; selecting a filter device; coupling said box culvert and saidfilter device; installing a platform disposed within the box culvert andunder the filter device, wherein the surface of the platform rests on asurface of the box culvert; and passing fluid through said box culvertand filter device. The space between a lower surface of the platform andan upper surface of the box culvert forms an alternate route for fluidflow.

In some embodiments, it is contemplated that the dimensions andstructural configurations of the box culvert and filter elements canvary with a range dependent on one or more design factors including butnot limited to: desired water volume capacity, desired weight of eachmodular unit, desired load-bearing tolerance for each unit, desiredamount of water flow to be managed, size and structure of overallassembly in which the system is to be used, and/or the desired accessspace for inspection and maintenance purposes. Other apparatuses,methods, features and advantages of the invention will be apparent toone with skill in the art upon examination of the following figures anddetailed description. All such additional apparatuses, methods, featuresand advantages are included within this description and are encompassedwithin the scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The included drawings are for illustrative purposes and provide examplesof possible structures for the disclosed inventive storm waterfiltration system. These drawings in no way limit any changes in formand detail that may be made to the invention by one skilled in the artwithout departing from the spirit and scope of the invention.

FIG. 1 illustrates a side cut-away view of a known filtration systemusing a vault configuration.

FIGS. 2A through 2C illustrate in top plan view, side cut-away view, andend view, respectively, a filtration system using box culverts with fivetreatment bays, an inlet section, and an outlet section. FIG. 2Dillustrates in side cut-away view of an embodiment of a bypass assemblyshown in FIGS. 2A through 2C.

FIG. 3 illustrates a top plan view of an exemplary filtration systemwith four banks

FIG. 4 illustrates in side cut-away view of a bank of the filtrationsystem described in FIG. 3.

FIG. 5 illustrates schematically a section placement diagram showing thefilter units described in FIGS. 3 and 4.

FIGS. 6A through 6D provide isometric views of one embodiment of a falsefloor of the present invention with recesses for four substantiallycylindrical filter devices.

FIGS. 7A through 7D provide isometric views of another embodiment of afalse floor of the present invention with recesses for eightsubstantially cylindrical filter devices.

FIGS. 8A through 8D provide isometric views of a further embodiment of afalse floor of the present invention with recesses for sixteensubstantially cylindrical filter devices.

FIGS. 9A through 9D illustrate one unit, a short end cap, made ofstandard concrete.

DETAILED DESCRIPTION

In the following detailed description, references are made to theaccompanying drawings, which form a part of the description and in whichare shown, by way of illustration, specific embodiments of the presentinvention. Although these embodiments are described in sufficient detailto enable one skilled in the art to practice the invention, theseexamples are not limiting. Other embodiments may be used, and changesmay be made without departing from the spirit and scope of theinvention.

One embodiment of the present invention includes a filtration systemwith multiple filter sections, each section containing filter media thatforms a treatment bay for incoming storm water. The filtration system isincorporated into a precast box culvert with a standard industry design.The box culvert is shown as a large pipe structure having a rectangularcross section, but in practice, the box culvert may have any other sizeand shape common known in the art, such as round, elliptical, circularor curved.

As shown in FIGS. 2A through 2C, storm water may enter the system froman inlet, for example, an opening with an entrance pipe 201, and flowthrough an inlet section 202. The ordinary artisan will recognize thatall or a portion of the top faces of each box culvert unit (alone or aspart of a larger assembly) can be fitted with or easily adapted forfitting with a cover panel, plug, plate, grate, fitting or valve systemwell known in the art of water management systems. As illustrated, theinlet section includes a bolted and gasketed access cover 203 and accessriser 204 with a ladder. The presence of this port allows forinspection, clean-out, monitoring, and maintenance of the inlet section.

One or more inlet bypass assemblies 205 are located within the inletsection. The bypass assembly includes two substantially vertical weirs.A first weir is located at a lower portion of the assembly and forms abarrier to the flow of storm water entering the inlet section andagainst which storm water can accumulate. The second weir is behind thefirst weir, preferably positioned such that the top edge of the secondweir is higher than the top edge of the first weir. The first weir canbe located in front of the second weir to first capture gross pollutantssuch as trash or debris. A floatables weir, which can also take the formof a gross pollutant hood, can be optionally located at a top portion ofthe assembly and at least partially obstructs the passage of trash andfloatables to the adjacent chambers. One or more steel plates may beused for or as part of one or more weirs. In addition, one or more pipesor flow thru tubes may be positioned through slots in the weirs toconvey fluid to the filter sections. In a preferred embodiment, two flowthru tubes may be incorporated to direct flow in a given bypassassembly. One or multiple bypass assemblies can be positioned within theinterior of a box culvert, downstream from the inlet opening. One ormultiple bypass assemblies can be placed side by side along a wall inthe inlet section. One or more filter sections 206 are placed downstreamfrom the inlet section. An equalization port 207 is placed in the inletsection (and in the outlet section, as well).

During periods of normal flow, storm water flows from the inlet sectionthrough the bypass assembly and toward downstream filtration media,where it is treated using filtration methods known in the art, includingfilter devices with filter cartridges or perforated sand pipes. In oneembodiment, the filter devices may be cylindrical in shape andmanufactured from durable polymeric components with a polymer-coatedsteel support screen and stainless steel hardware. Its base constructionallows use with a wide variety of media chose to address site-specificpollutants of concern. Additional access covers 209 and access riserswith steps 210 or ladder 211 can be included in the filter sections. Thepresence of these additional ports allows for inspection, clean-out,monitoring, and maintenance of the filter sections.

Subsequent filter sections of the system may be built into individualbox culverts or culvert segments placed side by side. To connect thesegments, tongue and groove joints 212 are sealed with asphalt masticand non shrink grout on the inside surfaces. An outlet section 208 islocated at an end of the filtration system and includes an outlet 213for storm water to exit the system.

As shown in FIG. 2C, the cross section of box culvert may be rectangularin shape. The box culvert has opposing sides and curved haunches 214 atthe corners. When positioned along one or more lower corners, thehaunches or shoulders of the box culvert provide a load-bearing surfaceto support a concrete slab that creates a false floor 215. The falsefloor may be made of concrete or other suitable materials. It is placedsubstantially horizontally above the bottom of the box culvert andcreates an annular space between the bottom of the false floor and thebottom surface of the box culvert. During periods of routine water flow,storm water moves through the three openings from the bypass assembliesto one or more filter sections for treatment. But during periods of highflow, storm water that has accumulated above the height of the secondweir travels from the entrance of the inlet section into the spacebetween the two weirs, bypasses the filter section, and exits throughthe outlet section or an alternative external bypass structure (such asa separate pipe).

When multiple filter sections are included, as shown in FIG. 2A and 2B,stainless steel false floor connector plates 216 can be used to connectfalse floors placed in adjacent filter segments.

An embodiment of the bypass assembly is shown in more detail in FIG. 2D.Under normal flow conditions, storm water from an entrance of the systemflows toward the first weir 216 and second weir 217. The storm waterrises to the level of one or more flow thru tubes 218. A floatables weir219 is positioned in front of an upper portion of the first weir andcaptures gross pollutants from the incoming storm water. Stormwater—i.e., “low flows”—passes through one or more of the tubes to thefilter medium 220. The floatables weir may be particularly advantageousin a system because allows the use of cartridges in the filter sectionwithout protection from floatable debris. During increased flow events,storm water passes over the first weir, into the space between the firstand second weirs, and underneath the false floor. In a preferredembodiment, a perforated drain-down feed-thru tube is placed along ornear one of the upwardly extending weirs. Because the lowest flow pathfrom the inlet section to either the filter section or the bypassassembly can be above the floor, there is the potential for standingwater. The perforated drain-down feed-thru tube allows that water todrain down into the filter section after the rain event has passed.

The design of the filtration system of the present invention isscalable. Because the box culverts are modular and can be added asneeded, the filtration system can be assembled in various configurationsto accommodate relatively high fluid flow along a space. FIG. 3illustrates one embodiment of the present invention that uses threehundred and sixty-eight (368) filter cartridges, each standing about 18inches tall. The system includes box culverts with an internal space inthe shape of cubes that houses the inlet and filter sections. The boxculverts are configured to form four substantially rectangular filterbanks, 301, 302, 303, and 304, each receiving storm water from inlet305. As a non-limiting example, each bank can be about 55 feet (660inches) long and 9.33 feet (112 inches) wide. The footprint of thesystem can be about 55 feet long (660 inches) and 37.33 feet (448inches) wide.

Storm water enters through an inlet section 306. One or more inletbypass assemblies 307 are located downstream from the entrance of eachbank. In a preferred embodiment, three bypass assembles are placed ineach of the four banks, providing for a total of twelve bypassassemblies. The inlet sections include equalizing boot couplers, 308 and309. During periods of routine flow, storm water moves from the inletsection through the bypass assembly, after which it is filtered byfilter cartridges 310 placed in the filter sections 311. The filteredflows are directed to one or more outlet sections 312, which alsoinclude one or more equalizing boot couplers 313, and exit the systemthrough an outlet 314 located on one side. False floors disposed withinthe box culverts under the filter cartridges provide a secondary routefor unfiltered bypass flows during period of high storm water flow.Stainless steel connecting plates 315 join false floors from adjacentfilter sections. By way of example, a filtration system configured inthis way may be designed to handle a treatment flow rate of about 6,624gallons per minute (14.76 cubic feet per second) and a bypass flow rateof about 15.9 cubic feet per second.

In this embodiment, storm water enters through a single inlet; filteredand unfiltered exits through a single outlet. However, the system can beconfigured to accept flow from additional inlets and additional outlets,such as external pipes or other structures. For example, unfilteredbypass flow can be directed to a separate pipe or manifold, from whichit would then exit the system.

Notably, the system of the present invention allows for flexibility inthe event that additional capacity is needed after installation.Although the filter banks are shown in the figures to be populated, inpractice, some of the filter banks may be left vacant. Plugs, such asstainless steel separation plates or other dividers, can be provided toisolate those unused banks during operation. As the filtration needs ofa particular site increases, filter devices with additional media may beadded in the previously unused banks, and the plugs can be removed toincrease the filtration capacity of a given system.

FIG. 4 shows an assembled side cut-away view of an installed system, asdescribed in FIG. 3. The system is placed on bedding 401 that conformsto American Public Works Association (“APWA”) Standard Specification,Section 306-1.121, except that the minimum bedding depth shall be12-inches or greater. Backfill added around the side and top 402,conforms to APWA Standard Specification, Section 306-1.121, except thatthe minimum side backfill width shall be as required to allow sufficientroom for compaction but no less than 6-inches and the minimum finalbackfill depth should be 12-inches. Compacted soil 403 may be placedabove the filtration system.

For cleanout and maintenance, bolted and gasketed access covers 404 maybe integrated using field poured concrete collar. The access covers maybe lifted to allow for maintenance, clean-out, or monitoring of a filtersection. In this way, the filtration system will not be clogged.Additional access risers with steps 405 or a ladder 406 can also beincluded to facilitate access into and out of a particular unit.

Between individual filter sections, tongue and groove joints 407 aresealed with asphalt mastic and non-shrink grout on one or more insidesurfaces. It is contemplated that in some embodiments, furtherconnecting means or fastening means may be provided for securing the boxculverts. For example, wires, plastic ties, fasteners (e.g., screws,rivets, nails, snap-clips, and the like) or adhesive means (e.g., tape,glue, and the like) may be used to secure box culverts. FIG. 5 is adiagram showing the section placement of the units in each filter bank.

The present invention uses the haunch or shoulder of the box culvert asa load-bearing surface, to support a false floor. This assembly providesfor a more economical design, as available standard precast concrete boxculverts may be used. It can also eliminate the need for separate pipingand the accompanying hydraulic issues that may arise, as bypass flowscan be directly to the annular space under the false floor.

As shown in more detail in FIG. 6, a false floor can be made of one ormore slabs of suitable material, such as concrete. The pre-existingstructure of the box culvert provides a supporting surface that can beused to support a false floor. At the two ends, the false floor includestop and bottom chamfers located along the shorter top and bottom sides601 and 602. Each chamfer is set at about a 45-degree angle to theadjacent face. The angles of the chamfers match those of thecorresponding haunches in the box culvert. During installation, thechamfers are aligned with the haunches of the box culvert to slide thefalse floor so that it rests in within the box culvert. Epoxy can beused to fill in the annular space between the false floor and boxculvert to create a seal and prevent leakage. When a system includesmultiple false floors, closure plates can be used to fill in the gapsbetween adjacent false floors.

The false floor includes one or more cartridge impression forms 603 thatcreate recesses, on which filter cartridges can rest. Threaded insertforms 604 are also included to be used with threaded inserts. Because ofit relatively compact size, this false floor with four filter recessesmay be placed at an outlet section, next to an outlet pipe.

Another embodiment of the false floor of the present invention is shownin FIGS. 7A through 7D. The false floor is made of standard concrete.Chamfers 701 and 702 located at the ends of the false floor can bedesigned to align with the haunches of a box culvert (not shown).Cartridge impression forms 703 located on the upper surface of the falsefloor create eight circular indentations on which eight circular filtercartridges can securely rest. Insert forms 704 are located along a sidefor threaded inserts. A through hole 705 can be placed at the center ofthe slab to secure the bypass assembly. Four standard lift eyes 706 canbe placed along a wall to facilitate transport. This false floor, whichincludes eight filter recesses, may be placed next to one or more bypassassemblies in an inlet section of a filtration system.

Yet another embodiment of the false floor with additional filtercartridges is shown in FIGS. 8A through 8D. Chamfers 801 and 802 locatedat the ends can be designed to align with the haunches of a box culvert(not shown). Cartridge impression forms 803 located on the surface offalse floor create sixteen circular indentations on which sixteencircular filter cartridges can securely rest. Threaded insert forms 804and 805 are located along two sides for threaded inserts. Through holes806 and 807 can be placed at the center of the slab to secure one ormore bypass assemblies. Four standard lift eyes 808 can be placed alonea wall to facilitate transport. This false floor may span the length, orat least the partial length, of a filter section.

FIGS. 9A through 9D shows an embodiment of a short end cap unit that canbe installed in a box culvert, for use in the filtration system of thepresent invention. Installation of this unit can involve a series ofconcrete pours to secure components of the system. In the first pour,the walls and end slabs 901 are secured. In the second pour, theinternal wall 902 is set in place. In the third pour, a gallery wallalong the bottom (not shown) can be set. Heavy-duty lift eyes 903 areplaced along the side walls to facilitate transport of the systems. Thewalls surrounding the aperture along a side, which can be offset to forma “stepped can,” may include two layers resulting in outside 904 andinside 905 walls.

The components of the present filtration system, including the bypassassemblies, false floor, filter sections, and banks can be placed indifferent positions and configurations to address storm water managementneeds along different surfaces and around different surface structures.For example, the false floor can be installed along side walls orunderneath vertical walls. Different filter media known in the art maybe used. In addition, the filtration system may be used alone or inconnection with other storm water management devices to increase thecapacity and improve processing of storm water. The box culverts may beattached to a retention or detention system for water storage. As afurther embodiment, a method of telemetric monitoring can beincorporated into the systems to better manage water flows.

Although the foregoing invention has been described in detail by way ofillustration and example for purposes of clarity and understanding, itwill be recognized that the above described invention may be embodied innumerous other specific variations and embodiments without departingfrom the spirit or essential characteristics of the invention. Certainchanges and modifications may be practiced, and it is understood thatthe invention is not to be limited by the forgoing details, but ratheris to be defined by the scope of the appended claims. Variousmodifications, alternative constructions, design options, changes andequivalents will readily occur to those skilled in the art and may beemployed, as suitable, without departing from the true spirit and scopeof the invention. Such changes might involve alternative materials,components, structural arrangements, sizes, shapes, forms, functions,operational features or the like.

What is claimed is:
 1. A filtration apparatus comprising: (a) a culvertcomprising an inlet opening, a pair of opposing side walls, a pair ofopposing haunches, and a bottom slab; (b) a filter bay disposed withinthe culvert, downstream from the inlet opening, the filter baycomprising (i) a base member disposed above the bottom slab andsupported by the opposing haunches of the culvert, (ii) filter mediumresting on the base member, and (iii) a bypass channel extendinglaterally between the base member and the bottom slab of the culvert;and (c) a bypass structure disposed between the inlet opening and thefilter bay, the bypass structure comprising (i) a first interior walldisposed on the bottom slab, (ii) a second interior wall disposed on thebase member and separated from the first interior wall by asubstantially hollow space, and (iii) a fluid conveying apparatusextending laterally through a portion of the bypass structure; whereinthe inlet opening and the filter medium are in fluid communicationthrough the fluid conveying apparatus of the bypass structure; andfurther wherein the inlet opening and the bypass channel are in fluidcommunication through the substantially hollow space of the bypassstructure.
 2. The filtration apparatus of claim 1, further comprising agross pollutant hood positioned in front of a portion of the firstinterior wall.
 3. The filtration apparatus of claim 1, furthercomprising a drain down tube downstream from the inlet opening.
 4. Thefiltration apparatus of claim 1, further comprising one or moresecondary culverts coupled to the culvert, each secondary culvertcomprising one or more filter bays.
 5. The filtration apparatus of claim4, further comprising one or more substantially vertical separationplates disposed between adjacent filter bays of adjacent culverts. 6.The filtration apparatus of claim 4, further comprising a secondaryculvert comprising an outlet section.
 7. The filtration apparatus ofclaim 4, further comprising a shared inlet pipe coupled to the inletopening, wherein a secondary culvert is adapted to receive fluid fromthe shared inlet pipe.
 8. The filtration apparatus of claim 1, furthercomprising secondary filter bays coupled to the filter bay.
 9. Thefiltration apparatus of claim 1, further comprising an access risercomprising a moveable access cover along a top surface of the culvert.10. The filtration apparatus of claim 1, further comprising a pluralityof bypass structures disposed within the culvert.
 11. The filtrationapparatus of claim 1, further comprising one or more intermediatesurfaces disposed between the first interior wall and the bottom slab.12. The filtration apparatus of claim 1, further comprising one or moreintermediate surfaces disposed between the second interior wall and thebase member.
 13. An apparatus adapted to cooperatively engage with aculvert comprising: (a) a culvert comprising one or more side walls, aninlet opening along at least one side wall, and a bottom slab; (b) afirst chamber disposed within the culvert and downstream from the inletopening; (c) a second chamber disposed within the culvert and downstreamfrom the first chamber, the second chamber comprising a base member,filter medium resting on the base member, and a bypass channel extendinglaterally between the base member and the bottom slab; (d) a bypass unitdisposed between the first and second chambers, the bypass unitcomprising a first interior wall, a second interior wall separated fromthe first interior wall by a substantially hollow space, and a fluidconveying apparatus extending laterally through a portion of the bypassunit; wherein the bypass channel forms a route for storm water exceedingthe capacity of the first chamber.
 14. The apparatus of claim 13,further comprising a gross pollutant hood positioned in front of aportion of the first interior wall.
 15. The apparatus of claim 13,further comprising a drain down tube in the first chamber.
 16. Theapparatus of claim 13, further comprising one or more secondary culvertscoupled to the culvert, wherein each secondary culvert comprises filtermedium.
 17. The apparatus of claim 16, further comprising one or moresubstantially vertical separation plates disposed between adjacentculverts.
 18. The apparatus of claim 16, wherein one of the secondaryculverts comprises an outlet section.
 19. The apparatus of claim 16,further comprising a shared inlet pipe coupled to the inlet opening,wherein a secondary culvert is adapted to receive fluid from the sharedinlet pipe.
 20. The apparatus of claim 13, further comprising an accessriser comprising a moveable access cover along a top surface of theculvert.
 21. The apparatus of claim 13, further comprising a pluralityof bypass units disposed between the first and second chambers.
 22. Amethod of processing fluid using a culvert comprising the steps of: (a)selecting an inlet of a culvert, the culvert comprising one or more sidewalls and a bottom slab; (b) passing fluid from the inlet of the culvertto a first chamber disposed within the culvert; (c) passing fluid fromthe first chamber through a bypass unit comprising a first interiorwall, a second interior wall separated from the first interior wall by asubstantially hollow space, and a fluid conveying apparatus extendinglaterally through a portion of the bypass unit; (d) releasing fluidaccumulating below the height of the first interior wall through thefluid conveying apparatus of the bypass unit to a second chamberdisposed within the culvert, the second chamber comprising a base memberdisposed above the bottom slab and filter medium resting on the basemember; and (e) releasing fluid accumulating above the height of thefirst interior wall through the substantially hollow space in the bypassunit to a channel extending laterally between the base member and thebottom slab.
 23. The method of claim 22, further comprising the step ofseparating gross pollutants through a floatables weir positioned infront of a portion of the first interior wall.
 24. The method of claim22, further comprising the step of removing fluid accumulating below theheight of the fluid conveying apparatus through a drain down tubepositioned in the first chamber.
 25. The method of claim 22, furthercomprising the steps of releasing filtered flows from the second chamberand releasing unfiltered flows from the channel.
 26. The method of claim22, further comprising the step of passing fluid exiting the culvertthrough one or more secondary culverts, each comprising filter medium.27. The method of claim 26, further comprising one or more substantiallyvertical separation plates disposed between adjacent culverts.
 28. Themethod of claim 22, wherein the culvert comprises secondary culvertscoupled to the second chamber.
 29. The method of claim 22, wherein theculvert further comprises an access riser comprising a moveable accesscover along a top surface of the culvert.
 30. The method of claim 22,further comprising the step of passing fluid from the first chamberthrough a plurality of bypass units.
 31. The method of claim 22, whereinthe channel between the base member and bottom slab forms an alternateroute for fluid flow.
 32. The method of claim 22, wherein said the firstchamber directs fluid flow via an equalizing port.
 33. The method ofclaim 22, wherein said the filter medium rests on one or more recesseson a surface of the base member.
 34. The method of claim 22, wherein ahole is used to position the bypass unit at a substantially centerportion of the base member.